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Join Date: Jun 2010
Posts: 14

Forward/Reverse (Electrical Interlocking) Motor

06/21/2010 11:56 AM

If the motor is forward direction, lifting the load some height, and suddenly the motor is off position. If again switched on, the motor will start. What is the problem? In the reverse direction the motor is working perfectly.

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#1

Re: forward/reverse(electrical interlocking)

06/21/2010 12:15 PM

Murphy's and Newton's laws tag teamed against you.

Might be too much load too far up. Trying to start fully loaded and part way up.

Have you tried lowering the load all the way down then starting over again?

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Guru
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#2

Re: forward/reverse(electrical interlocking)

06/21/2010 12:44 PM

It would help to know what kind of an electric motor you have, how large of a load is being lifted and what you mean by an off position. Most motors when turned actually OFF (no voltages applied to stator and possibly rotor windings) will spin fairly freely and thus will not support a load raised to a certain position. So something else is happening in your rig that you are not telling us. This is probably because you don't know the mechanism fully yet.

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#3

Re: Forward/Reverse (Electrical Interlocking) Motor

06/21/2010 9:04 PM

Boy,

I must be really thick. Here's my interpretation of the OP's question.

"If the motor is forward direction," means: motor energized, running properly.

"lifting the load some height" Motor loaded, lifting a load.

" suddenly the motor is off position." Motor de-energized. Unknown if load freewheels. If winch, no. If other means of lift, unknown.

"If again switched on, the motor will start" means: motor energized, running properly.

"What is the problem?" What is the problem?

"In the reverse direction the motor is working perfectly."

Please define "motor is working perfectly."

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#8
In reply to #3

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 7:48 AM

The question itself is problem. It is unclear and confusing. It is suggested that person posing question should give following information:-

1.Full Name of the person.

2.Location.

3.Detailed description of the problem including the sketches, pictures, graphs etc.

4.Detailed application of the equipment.

5.End product.

I would request CR4 Admin. to revise the format of asking questions so that persons who are willing to help have not to waste time in understanding the problem or asking for the more details.

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#4

Re: Forward/Reverse (Electrical Interlocking) Motor

06/21/2010 9:33 PM

jvsnlchari

Why do you include the words "Electrical Interlocking" in your title?

Just curious.

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#5

Re: Forward/Reverse (Electrical Interlocking) Motor

06/21/2010 10:58 PM

At a guess due to the information provided the overload for the contactor is probably set to automatic reset, meaning after the motor overload trips it will automatically reset itself enabling you to just hit the start button again and away it will go until it trips again. If the time frame lengthens between when the motor stops and you can restart it this means the thermal device is taking longer to cool down and reset itself.

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#6
In reply to #5

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 12:11 AM

Bingo!

As a field and phone support guy, I deal with these kind of Cryptic / Hieroglyphic descriptions quite a bit... No fault of anyone, just the way it is...

I give you a GA Grochy, as i think you nailed it!

Your answer was my train of thought as well... nicely done.

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#9
In reply to #6

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 9:19 AM

johnnybravo,

As tech support (and complaint department) for the North and South American continents for our products, I know where your coming from.

My favorite: It don't work!

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#7

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 7:00 AM

if u provide little more info, tht would be helpful...........anyway check out ur forward n reverse rotation control circuit.....thn check ur olr settings......check what type of starter have u used so tht torque during forward operation s sufficient.............check torque requirement.......

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#10

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 11:13 AM

I assume you are using a leadscrew. There is an alternative.

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#11
In reply to #10

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 3:38 PM

I would not make that assumption. I picture a spool that winds up a cable. As the weight goes up, the diameter of the cable on the spool increases, increasing the current in the motor. When the current reaches a limit (which could be adjustable), it trips, and the motor stops.

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#18
In reply to #11

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 5:52 PM

okay that makes sense too.

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#12

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 4:17 PM

A clue (because I don't know) would be the up contactor sees more current whilst doing the lifting than the down contactor sees doing the "downing".

There is something faulty about The up contactor (perhaps if it is three phase, a contact problem that would cause intermittent single phasing?).

If it is indeed an electrical interlock, I have had problems with the auxiliary switches, maybe this mysterious person is to?

Go ahead, I can take it.

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#13
In reply to #12

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 4:32 PM

What if is is something simple?

could be a mechanical problem with the lifter causing drag thus overloading the system?

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#14
In reply to #13

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 4:57 PM

I agree farmatt. I just wanted to see how complicated I could make it.

Most of these hoists have a disk brake tied to the interlock and if this brake comes in when it is not supposed to.....

Anyway, I foresee a pile of various parts from a hoist in a box somewhere in a corner.

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#15
In reply to #14

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 5:19 PM

how do you know what kind of hoist it is?

am I missing part of his question or something?

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#16
In reply to #15

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 5:26 PM

I don't know, I was just guessing.

The OP did not give much information.

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#17
In reply to #16

Re: Forward/Reverse (Electrical Interlocking) Motor

06/22/2010 5:30 PM

I thought for a second there that I was really becoming as dumb as I look!!!

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